Demonstrations of phase shifting and entrainment of human circadian rhythms by timed exposure to artificial bright light have a number of important applications in the treatment of jet lag, shiftwork maladaptation, and other circadian sleep-wake disorders. The long-term objectives of this grant application are to develop a practical and effective means of phase shifting circadian rhythms following transmeridian travel, thereby minimizing the duration and severity of jet lag. Bio-Brite has pioneered the development of a head-mounted Light Visor that is easily carried along on long-distance flights, and that affords the user several advantages over traditional bright light boxes and rooms. Phase I of the project will test the efficacy of a new prototype of the Light Visor in accelerating circadian reentrainment and alleviating jet lag in 20 volunteers following a westward flight across 6 time zones (Zurich-New York). Pre- and post-flight salivary melatonin levels will provide estimates of circadian phase, while actigraphy, performance testing, and subjective scales will provide indices of jet lag severity. These data are expected to lead to further refinements of the Light Visor, and more extensive validation, in Phase II of the project, on groups of travelers following eastward and westward flights across 6-10 time zones. PROPOSED COMMERCIAL APPLICATION: The International Air Transport Association (LATA) estimated that over 250 million international flights were taken in 1990; many of these involve crossing multiple time zones. Thus, a scientifically validated, practical, and affordable non-drug jet lag treatment program, marketed internationally as a consumer product, can potentially generate annual revenues in the multimillion dollar range.